Sulphide colours on metallic copper

In view of the criticism of Tammann and Koster's investigations, by Evans, who remarks that they seem to have applied the interference theory to their results wrongly, it is evident that further investigation is necessary. The sulphide colour sequence differs considerably from the oxide sequence of colours, and spectrophotometric observations were made to trace the cause of the divergence. The attack of a mixture of pure hydrogen sulphide and oxygen in equal volumes on pure metallic copper is rapid, and depends on the nature of the exposed surface, but the time for two complete colour sequences to be produced is of the order of three minutes. It is thus evident that no accurate photometric observations can be obtained, unless the progress of the reaction be stopped at various stages by removing reacting gases from the vessel by a pump. In practice it was found that there was some difficulty in getting complete sequences in this way. Thus it is necessary to slow down the rate of production of the colour sequences, and this was accomplished by coating the metal with an invisible oxide film. The cold activated metal was left in air for periods varying from 5 minutes to 1 hour. The oxide film so formed reduces very considerably the rate at which the colour sequences are produced, so that they may be observed conveniently with the spectrophotometer, in the apparatus here described, while the reaction is in progress. If the surface be exposed to air for too long a period, the brightness of the colour sequence is much diminished.

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Characterization of Intergranular Corrosion Defects in a 2024 T351 Aluminium Alloy

Materials Science Forum ◽

10.4028/www.scientific.net/msf.877.444 ◽

2016 ◽

Vol 877 ◽

pp. 444-449 ◽

Cited By ~ 1

Author(s):

M.L. de Bonfils-Lahovary ◽

L. Laffont ◽

Christine Blanc

Keyword(s):

Oxide Film ◽

Intergranular Corrosion ◽

Ion Beam ◽

Metallic Copper ◽

Analytical Techniques ◽

Propagation Rate ◽

Structural Defects ◽

Alumina Oxide ◽

Corrosion Defects ◽

Focus Ion Beam

In the 2xxx series alloys, intergranular corrosion is generally related to the strong reactivity of copper-rich intergranular precipitates leading to a copper enrichment of these particles. While the nature of the oxides formed inside the intergranular corrosion defects was assumed to strongly influence the intergranular corrosion propagation rate, it was not clearly identified due to the thickness of the oxide layer formed which required to use high resolution analytical techniques. The present work aims to characterize the intergranular corrosion defects formed for a 2024-T351 aluminum alloy after a 24 hours continuous immersion in a 1 M NaCl solution and compares the results to literature data concerning the oxide layers formed on copper-rich model alloys. A combination of focus ion beam (FIB) technique, transmission electron microscopy (TEM) observations and energy dispersive X-Ray spectroscopy (EDX) analyses was used to accurately characterize both the morphology and chemical composition of the intergranular corrosion defects. Results evidenced the dissolution of intergranular copper-rich particles, the formation of a 10-200 nm-thin metallic copper-rich layer at the oxide/metal interface and the incorporation of copper inside the amorphous alumina oxide film leading to the formation of structural defects of the oxide film.

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The cause of the colours shown during the oxidation of metallic copper

Proceedings of the Royal Society of London. Series A, Containing Papers of a Mathematical and Physical Character ◽

10.1098/rspa.1927.0111 ◽

1927 ◽

Vol 115 (772) ◽

pp. 570-588 ◽

Cited By ~ 24

Keyword(s):

Thin Films ◽

Oxide Film ◽

Copper Oxide ◽

Cupric Oxide ◽

Metallic Copper ◽

Oxide Films ◽

Copper Surface ◽

Considerable Time ◽

Pass Through

During the initial stages of the oxidation of a clean metallic copper surface, and before the normal black colour of cupric oxide is finally attained, bright colours appear which pass through the first and second orders of the series of colours observed and tabulated by Newton as characteristic of thin films of air of increasing thickness. These facts have been known for a considerable time, but though the interference colours of thin films of air and those of the oxide film are produced in the same order, grave doubts have existed as to whether interference was the cause of the colours shown by the copper. This problem has been approached from measurements of the intensity of the light reflected from copper oxide films of known thickness, and the results show that interference is actually the cause of the production of the colour, though the result is complicated by the opacity of the film, the dispersion of the oxide, and the scattering of the light complementary to the film colour when the metal is burnished.

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Searching for optical companions to four binary millisecond pulsars with the Gran Telescopio Canarias

Monthly Notices of the Royal Astronomical Society ◽

10.1093/mnras/staa066 ◽

2020 ◽

Vol 492 (2) ◽

pp. 3032-3040 ◽

Cited By ~ 1

Author(s):

A Yu Kirichenko ◽

A V Karpova ◽

D A Zyuzin ◽

S V Zharikov ◽

E A López ◽

...

Keyword(s):

White Dwarf ◽

White Dwarfs ◽

Optical Data ◽

Pure Hydrogen ◽

Millisecond Pulsars ◽

Upper Limit ◽

Photometric Observations ◽

Low Mass

ABSTRACT We report on multiband photometric observations of four binary millisecond pulsars with the Gran Telescopio Canarias. The observations led to detection of binary companions to PSRs J1630+3734, J1741+1351, and J2042+0246 in the Sloan g′, r′, and i′ bands. Their magnitudes in the r′ band are ≈24.4, 24.4, and 24.0, respectively. We also set a 3σ upper limit on the brightness of the PSR J0557+1550 companion in the r′ band of ≈25.6 mag. Combining the optical data with the radio timing measurements and white dwarf cooling models, we show that the detected companions are cool low-mass white dwarfs with temperatures and ages in the respective ranges of (4–7) × 103 K and 2–5 Gyr. All the detected white dwarfs are found to likely have either pure hydrogen or mixed helium–hydrogen atmospheres.

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Formation of sulphur compounds in the hydrodenitrogenation of 2-methylquinoline, 2-methylpiperidine, indole, and isoquinoline on a nickel-tungsten catalyst in the presence of hydrogen sulphide

Collection of Czechoslovak Chemical Communications ◽

10.1135/cccc19833413 ◽

1983 ◽

Vol 48 (12) ◽

pp. 3413-3420 ◽

Cited By ~ 3

Author(s):

Mirko Černý ◽

Antonín Trka

Keyword(s):

Reaction Mechanism ◽

Hydrogen Sulphide ◽

Neutral Fraction ◽

Degree Of Conversion ◽

Pure Hydrogen ◽

Sulphur Compounds ◽

Nickel Tungsten

2-Methylquinoline, 2-methylpiperidine, indole, and isoquinoline were subjected to hydrodenitrogenation (HDN) on a sulphidized nickel-tungsten catalyst in an autoclave at 300 and 350 °C using pure hydrogen or a hydrogen-hydrogen sulphide mixture. The neutral fraction from the HDN of 2-methylquinoline and 2-methylpiperidine contained 40 and 90% sulphur compounds, respectively. The presence of hydrogen sulphide in the HDN of isoquinoline resulted in an enhanced fraction of the neutral moiety. A reaction mechanism is suggested for the HDN of 2-methylquinoline and 2-methylpiperidine in the presence of hydrogen sulphide, in which the latter contributes to the higher degree of conversion due to the formation of corresponding sulphur compounds.

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Operating Microtubular SOFCS With Hydrogen Chloride and Hydrogen Sulfide Containing Fuels and Synthetic Wood Gas

Journal of Fuel Cell Science and Technology ◽

10.1115/1.2205361 ◽

2006 ◽

Vol 3 (3) ◽

pp. 280-283 ◽

Cited By ~ 12

Author(s):

Gerhard Buchinger ◽

Paul Hinterreiter ◽

Thomas Raab ◽

Stefan Griesser ◽

Richard Claassen ◽

...

Keyword(s):

Carbon Dioxide ◽

Fuel Cells ◽

Fuel Cell ◽

Solid Oxide Fuel Cells ◽

Hydrogen Chloride ◽

Hydrogen Sulphide ◽

Solid Oxide ◽

Pure Hydrogen ◽

Oxide Fuel ◽

Pyrolysis Gas

Solid oxide fuel cells are known to be able to handle a large variety of different fuels. Because of the greenhouse effect the use of carbon dioxide neutral gases or liquids are of special interest. In this context wood-gas has a big potential to be an alternative fuel for solid oxide fuel cells (SOFCs). The gas is generated by a fluidized bed steam gasifier and consists of various components such as 25 Vol % carbon monoxide, 20 Vol % carbon dioxide, 10 Vol % methane, 2.5 Vol % ethylene, 0.5 Vol % propylene, 2 Vol % nitrogen, and the rest hydrogen (values in dry state). The water concentration of the original pyrolysis gas is about 35 Vol %. Besides these main ingredients there are of course many impurities like dust, tars, ammonia, hydrogen sulphide, and hydrogen chloride present in the product gas. Especially the last two ones may lead to degeneration of the fuel cell anode and must therefore be almost totally removed before feeding the gas into the cell. In order to reduce energy losses, hot gas cleaning systems are favored. This, however, limits the possibility to reduce the impurity concentrations to very low levels. Therefore the aim of this work is to define the maximum acceptable output concentrations for the hydrogen chloride adsorber also in combination with hydrogen sulphide, since for a micro-tubular SOFC there are as yet hardly any data available. In order to determine the influence of the hydrogen chloride on the performance of the fuel cell, different concentrations of this impurity were fed to the cell. Here, also the flow rate was changed while the electrochemical output was determined. In addition it was analyzed if there were any effects when changing from pure hydrogen to the HCl containing fuel. This was investigated at 1123 K and 1173 K, which are the preferred working temperatures for our cells. Cooling down as well as heating up procedures were tested with cells between 1173 K and 573 K. In a second series of experiments, combinations of hydrogen chloride and hydrogen sulphide of variable concentrations were tested. As before, changing between pure hydrogen and the acid containing fuel at above given temperatures was analyzed by determining the cell performance. In parallel to the above experiments, synthetic wood gas was used for operating the microtubular fuel cell while monitoring the electrochemical output with time.

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Ribosome Structural Organization

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100051670 ◽

1974 ◽

Vol 32 ◽

pp. 332-333

Author(s):

James A. Lake

Keyword(s):

Ribosomal Proteins ◽

Structural Organization ◽

Three Dimensional ◽

Small Subunit ◽

Structural Studies ◽

X Ray Diffraction ◽

Specific Antibodies ◽

X Ray ◽

E Coli ◽

Complete Sequences

The understanding of ribosome structure has advanced considerably in the last several years. Biochemists have characterized the constituent proteins and rRNA's of ribosomes. Complete sequences have been determined for some ribosomal proteins and specific antibodies have been prepared against all E. coli small subunit proteins. In addition, a number of naturally occuring systems of three dimensional ribosome crystals which are suitable for structural studies have been observed in eukaryotes. Although the crystals are, in general, too small for X-ray diffraction, their size is ideal for electron microscopy.

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Deposited emulsion particles in the pores of aluminum oxide film

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100109392 ◽

1978 ◽

Vol 36 (1) ◽

pp. 450-451

Author(s):

Michio Ashida ◽

Yasukiyo Ueda

Keyword(s):

Oxide Film ◽

Acid Solution ◽

Barrier Layer ◽

Colloidal Particles ◽

Oxalic Acid Solution ◽

Anodic Oxide ◽

Anodic Oxide Film ◽

Carbon Replica ◽

Sectioning Method ◽

Thin Sectioning

An anodic oxide film is formed on aluminum in an acidic elecrolyte during anodizing. The structure of the oxide film was observed directly by carbon replica method(l) and ultra-thin sectioning method(2). The oxide film consists of barrier layer and porous layer constructed with fine hexagonal cellular structure. The diameter of micro pores and the thickness of barrier layer depend on the applying voltage and electrolyte. Because the dimension of the pore corresponds to that of colloidal particles, many metals deposit in the pores. When the oxide film is treated as anode in emulsion of polyelectrolyte, the emulsion particles migrate onto the film and deposit on it. We investigated the behavior of the emulsion particles during electrodeposition.Aluminum foils (99.3%) were anodized in either 0.25M oxalic acid solution at 30°C or 3M sulfuric acid solution at 20°C. After washing with distilled water, the oxide films used as anode were coated with emulsion particles by applying voltage of 200V and then they were cured at 190°C for 30 minutes.

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